The use of medicament inhalers for the treatment of respiratory diseases is well known. A common type of medicament inhaler is what is known as a pressurised Metered Dose Inhaler (pMDI). The construction and operation of pMDIs is well known and described in prior art.
Another common type of medicament inhaler is what is known as a Dry Powder Inhaler (DPI). The construction and operation of DPI's is also well known and described in prior art.
Further examples of medicament inhalers include delivery devices such as nebulisers and nasal sprays. Such delivery devices are generally designed to supply a dose of medicament in the form of a fine mist, which is directed either into the month or nasal cavity of a user.
A problem or difficulty associated with the use of medicament inhalers generally is poor medicament compliance, particularly in relation to the use of preventer medicament inhalers. That is, many studies have shown that users frequently do not take their medicament at the predetermined or prescribed times and/or in the required amounts.
The consequences of this non-compliance are reduced disease control, lower quality of life, lost productivity, hospitalisation and avoidable deaths.
Not only is compliance to preventative medicaments typically low, but it has also been shown that actual compliance by a user is lower than the same user's estimated compliance.
In order to address the issue of poor medicament compliance, there are available a number of compliance monitoring devices for use with medicament inhalers. Examples include those described in U.S. Pat. No. 6,958,691 Anderson; U.S. Pat. No. 8,342,172 Levy; U.S. Pat. No. 6,202,642 McKinnon; U.S. Pat. No. 5,544,647 Jewett; U.S. Pat. No. 8,464,707 Jongejan; US2014/0000598 Sutherland; U.S. Pat. No. 8,424,517 Sutherland; WO 2013/043063 Sutherland; and NZ622000 Sutherland.
Some of these prior art devices include a detection means to determine when a canister of medicament has been inserted into and/or removed from an actuator of a pMDI. Examples include US2014/0000598 Sutherland and WO 2013/043063 Sutherland.
Furthermore, US2014/0000598 Sutherland discloses a detection means for determining if a pMDI actuator (containing a canister of medicament) has been placed into and/or removed from a releasably attachable compliance monitor housing. Likewise, NZ622000 Sutherland discloses a detection means for determining when a compliance monitor has been attached to and/or removed from a DPI. US2014/0000598 Sutherland also discloses an optical dose counter which may be adapted to determine any deterioration of the inner surfaces of the medicament inhaler.
However, none of the above three compliance monitors are capable of identifying the medicament delivery device they are attached to.
Medicaments used to control asthma are broadly grouped into three classes: relievers, preventers, and long acting relievers. In addition, there are also available combination medicaments which combine both a reliever and a preventer medicament. These classifications can also be applied to the inhalers themselves (both pMDI's and DPI's).
A reliever (or rescue) medicament (or inhaler) is used in a specific event or emergency, for example, if a person were to have a sudden asthma attack. A reliever medicament generally contains a bronchodilator used to open up the airways (e.g., Bricanyl® TURBUHALER® by AstraZeneca). The relievers are fast acting and in most cases will relieve (or reduce the severity of) an asthma attack, almost instantaneously.
Preventer (or controller) medicaments are designed for regular use in order to prevent an asthma attack from occurring and/or to manage or control asthma. They treat the underlying inflammation in the airways and generally contain corticosteroids (e.g., Pulmicort® TURBUHALER® by AstraZeneca). The regular use of a preventer by asthma sufferers is generally effective in controlling the disease and/or preventing the vast majority of asthma attacks. Commonly, preventers are taken twice a day, usually at a set time in the morning and in the evening. Importantly, a preventer will not relieve an acute asthma attack that has already started.
Long acting reliever medicaments (or long acting rescue medicaments) generally contain long acting bronchodilators (e.g., Oxis® TURBUHALER® by AstraZeneca). Long acting reliever medicaments should be taken regularly and are often taken together with preventers.
Symbicort® TURBUHALER® by AstraZeneca is an example of a combination medicament.
To assist patients with treatment regime compliance and/or to enable them to distinguish between their different medicaments, pharmaceutical companies generally colour-code their medicaments and/or inhalers.
For example, a blue colour is often used for reliever medicaments (e.g. Bricanyl® TURBUHALER®, Ventolin® pMDI); an orange or brown colour is often used for preventer medicaments (e.g. Plumicort® TURBUHALER®, Flixotide® pMDI); long acting relievers, such as Oxis® TURBUHALER® are often green/blue; a red colour is often used for the actuator (base) of the combined preventer and reliever (e.g., Symbicort® TURBUHALER®) and purple for pMDI combination inhaler (Seretide®).
Patients suffering from respiratory conditions are usually prescribed at least two of these types of medicaments in order to properly manage and/or treat their condition (typically a reliever medicament and a preventer medicament).
Notwithstanding the differences in outer appearance (colour) of the inhalers, patients nonetheless often use the wrong medicament for the intended purpose. For example, they use a reliever where a preventer should be used or vice versa, or use a reliever when a long acting reliever should be used.
It will be appreciated that problems may occur if the patient inadvertently uses the wrong medicament, for example, if they use a reliever medicament where a preventer medicament should have been used or vice versa; or if they were to use a reliever medicament when a long acting reliever should have been used, and so on.
Having regard to the forgoing, it may be of advantage if there was available a compliance monitoring device capable of distinguishing between the different types of medicaments and/or inhalers—with a view to possibly alerting the patient (or a healthcare professional) if the wrong medicament or inhaler has been (or is about to be) used.
In U.S. Pat. No. 7,191,777 Brand and U.S. Pat. No. 7,819,116 Brand there is described a medicament dispenser system which uses radio frequency identification to identify the medicament used in conjunction with the actuator. A key disadvantage of both Brand patents is that the identification method requires modification of the medicament delivery device through: (a) the addition of a RFID tag to the medicament canister and (b) the addition of a RFID reader to the actuator. Furthermore, the solution proposed by both Brand patents is complex and not cost effective.
Optical proximity sensors, colour sensors and sensors combining both are well known in the art.
Optical proximity sensors such as those described in U.S. Pat. No. 8,232,883 Yao comprise an integrated infrared emitter or light source and a corresponding photodiode or light detector embedded into a housing and connected to a light detector sensing circuit. U.S. Pat. No. 8,232,883 Yao describes an optical sensor comprising infrared light (IR) emitter (E) and IR detector (D) mounted on a substrate. The axis of the IR E and IR D are parallel and vertical. Two spherical lenses are placed over the IR E and IR D to collect and direct the light either onto the object to be detected (lens over IR E) or to the IR D (lens over IR D). The sensor also comprises a light shield dividing the sensor into a light emitting and light detection portions, to minimize the crosstalk, increase the detection distance, reducing the size, volume and footprint of the sensor and manufacturing costs.
We have previously described compliance monitoring devices which use optical sensors for dose detection in our NZ Patent No. NZ 574666 Sutherland. The optical sensor could be adapted to monitor and/or store data relating to when a medicament container has been removed from and/or placed into the actuator. However, the devices of our earlier invention did not have the function of identifying the type of medicament delivery device being monitored.
Photoelectric colour sensors generally comprise three light emitters, each generating wavelength bands corresponding to red (R), green (G) and blue (B) respectively, a lens for emitting the light from each emitter to the object to be detected and a light receiver. The R, G, B light is emitted at the object in a pre-set order. The colour of the object is determined by reference to the ratios between the red, green, and blue wavelengths reflected by the object as detected by the receiver. U.S. Pat. No. 6,323,481 Ueki describes a fibre-type photoelectric switch which is capable of detecting presence, absence, the shape, dimensions and colour of an object on the basis of the reception of reflected light.
Chip colour sensors generally contain an array of red, blue and green filter photodiodes in various arrangements. The light signal from the photodiodes is converted to a frequency (light-to-frequency converter, e.g. TCS3772) or to a digital signal (light-to-digital converter, e.g., TAOS TCS230) and then the conversion result is transferred to the corresponding data registers in the microcontroller for processing. The digital signal intensities are compared to determine the predominant colour in the guided light and hence the predominant colour of the object.
Compliance monitoring devices are relatively small, portable and light. Any sensor incorporated into a compliance monitor has to be small, light-weight, have low-power use and low manufacturing cost and be capable of detection at very short distances, with a preferred range being between 0.1-5 mm, even in cases of non-reflective surfaces.
There are available optical detection systems whereby a light emitter is placed next to a light receiver, and whereby the axis of the light emitter (or light emitted) is parallel to the axis of the light receiver (that is, both axes are usually vertical). In such a system, the light receiver is able to receive and/or detect light emitted by the light emitter, after it has been reflected off the surface of an adjacent object, thereby identifying that the object is present. However a disadvantage, or limitation, of such a system is that it only works for object surfaces that are reflective. If the surface of the object is non-reflective and/or absorbent, then most of the light emitted will be absorbed rather than reflected, and hence no significant amount of reflected light will be received and/or detected by the light receiver. In such instances the light receiver may erroneously conclude that no object is present.
There are also available optical detection systems in which the axis of the light emitter is angled towards the axis of the light receiver (e.g. Omron EE-SY190/191), but their detection range renders them not suitable for use in compliance monitors.
While optical colour sensor chips (e.g., TAOS TCS3772 colour light-to-digital converter with proximity sensor) generally fit the size and detection distance criteria, there are some disadvantages associated with their use in compliance monitors:                Cost—colour sensor chips are relatively expensive and furthermore they require additional parts such as external visible and infrared LED illumination sources.        Power usage—the sensor chips contain internal processing and have significantly higher times for initialisation and signal acquisition leading to higher power consumption.        Sensitive to ambient light—the sensor chips are prone to saturation due to the use of the visible light range and relative intensity of the illumination source.        
WO2014/023763 Schabbach describes a supplemental device for a pen-type injection device, which includes a quantity determiner for determining a quantity of medicament that has been dispensed. In one embodiment, the quantity determiner comprises a light source and a photo sensor, operatively connected to a processor arrangement which is configured to interpret signals provided by the photo sensor to determine the quantity of medicament that has been delivered.
WO2013/109913 Bear describes a medication storage device which includes an imaging system, comprising a plurality of image capturing devices, to capture images of the medication dose containers. However, the invention described in Bear only discloses the use of a camera—type device to capture these images, and furthermore, the image capturing devices described in Bear are only adapted to capture images of the interior region of each dose container.
WO2011/073806 Denyer describes a monitoring device which includes a housing adapted to be releasably attached to a drug delivery device. The housing includes a colour detector adapted to detect and/or identify a colour associated with the drug delivery device. The colour detector described in Denyer comprises a plurality of light sources adapted to produce different coloured light, and a colour-sensitive photodetector for determining the colour of the drug delivery device, based on the reflected coloured light. Hence, one limitation associated with Denyer is that it is only able to utilise visible (or coloured) light sources.